Propulsion-Release Safety Vacuum Release System

ABSTRACT

Abstract of Disclosure 
     A propulsion-release safety vacuum release system (SVRS) for swimming pools monitors vacuum level in a suction pipe and reverses flow within the suction pipe if vacuum level exceeds a predetermined level.  Thus, if a bather becomes entrapped on a suction outlet such as the pool main drain, the SVRS system not only releases the vacuum but also pushes away the suction-entrapped bather.  In response to an elevated vacuum level, a vacuum-monitoring device actuates an automatic valve, which reverses fluid communications between the influent and effluent conduits of the pump and filter system.  In this process, the suction pipe is converted from vacuum (negative pressure) to positive pressure.  Thereafter, the automatic valve system automatically resets the SVRS to the original or normal flow configuration.  The SVRS functions without interrupting operation of the swimming pool filtration system.

Cross Reference to Related Applications

[0001] This application claims the benefit of United States Provisional Patent Application Serial No. 60/337,893 filed December 10, 2001, pending.

Background of Invention

[0002] Field of the Invention -- In one aspect, the invention generally relates to fluid handling. More specifically, it relates to the use of line condition change responsive valves. In a second aspect, the invention generally relates to pool type baths. More specifically, it discloses a method of utilizing a flow control valve to prevent vacuum entrapment against suction fittings in swimming pools, wading pools, and hydrotherapy pools. Further applications include any pump suction system that would benefit from a method of automatically clearing a suction intake of blockages.

[0003] Description of Prior Art -- A number of inventions provide protection to bathers who become entrapped onto a suction outlet fitting in a swimming pool. These devices are categorized as safety vacuum release systems (SVRS).

[0004] A first type of SVRS utilizes a safety relief valve that senses the increase in vacuum level caused by a blockage of flow. The valve immediately introduces atmosphere to the suction system to neutralize a high or dangerous level of vacuum. United States Patent No. 6,098,654 to Cohen and Meyer discloses a valve capable of operating in this mode. When the valve introduces atmosphere into a suction line, it may allow a back flow of water under force of gravity from elevated portions of the piping system. This back-flowing water, if present, can assist in freeing an entrapped bather from a suction fitting. The valve operates by selectively positioning a dynamic plug to open or close a flow path to atmosphere, according to the level of vacuum in the suction system. At a pre-selected vacuum level, a triggering device causes the valve to be tripped, with full actuation of the dynamic plug into a locked-open position. Full tripping provides unequivocal release of a trapped bather. Also, it requires a manual reset of the valve and of the swimming pool circulation system, which encourages the pool operator to inspect the system for safety. This valve also is adaptable for use in the present, improved system and method.

[0005] A second type of SVRS incorporates an electrical vacuum level-sensing device. If vacuum level increases to a dangerous level, the sensing device shuts off the circulation pump to allow the vacuum level to quickly diminish.

[0006] A third type of SVRS is a vertical vent pipe in fluid communication with the pool drain line, installed below the pool water level, and vented to atmosphere at the upper end. During normal operation of the circulation system, the water level within the vent pipe drops approximately one foot below the pool water level per inch of mercury vacuum level within the suction pipe. If a bather becomes entrapped against the pool suction outlet fitting, which usually is the main drain fitting located at the deepest point of the pool floor, the increase in vacuum level will cause the vent pipe to evacuate to the suction line and will allow atmosphere into the pipe, which neutralizes the high level of vacuum resulting from the blockage.

[0007] All three types of known SVRS leave the swimming pool circulation system inoperative after they have been activated. Therefore, a system that would quickly release the entrapped bather without interrupting the continuity of operating of the circulation system would be desirable. The swimming pool circulation system should continually provide cleaning, filtration, sanitization, and heating of the pool water.

[0008] All three types of SVRS release the entrapped victim but provide no adequate means to remove the victim from the suction outlet fitting. Therefore, an SVRS that incorporates a means to forcibly move the victim away from the suction outlet fitting under pump-forced pressure would be desirable.

[0009] When actuated, two of the three types of SVRS now available introduce air into the circulation system. Air within a swimming pool circulation system is a problem, as it causes the pump to lose prime and must be released manually before the system can be returned to operation. It would therefore be desirable to provide an SVRS that does not introduce air into the circulation system.

[0010] All three types of SVRS must be isolated or disabled for swimming pool vacuum cleaning operations. This is because the higher level of vacuum needed for vacuum- cleaning operations could activate the SVRS, shutting down the circulation system and, consequently, the vacuum cleaning operation. Therefore, it would be desirable to provide an SVRS that does not interrupt swimming pool vacuum cleaning operations.

[0011] To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.

Summary of Invention

[0012] Against the described background, a general object of the invention is to provide an SVRS that converts a dangerously high level of vacuum into pump-forced pressure by reversing the direction of water flow within a suction pipe connected to a flow-blocked suction outlet fitting.

[0013] A related object of the invention is to provide a system that reliably releases and pushes away an entrapped victim by creating a substantial pressurized incoming flow stream at the suction outlet fitting.

[0014] Optionally, another object is to provide an SVRS that performs the safety function of releasing an entrapped bather without stopping the operation of the swimming pool circulation system.

[0015] Optionally, another object of the invention is to provide a system that can, at the operator's election, either be adjusted to automatically reset itself after actuating to clear a flow-blocked suction outlet fitting or be adjusted to require a manual resetting after each actuation.

[0016] Another object of the invention is to provide an SVRS capable of performing a release function without introducing air into the pool circulation system.

[0017] A desirable object of the invention is to provide a vacuum release system that does not interfere with swimming pool vacuum cleaning operations.

[0018] Another object of the invention is to provide an SVRS that is easily designed into a new swimming pool before construction.

[0019] Another object of the invention is to provide an SVRS that can be easily retrofitted to an existing swimming pool to eliminate built-in suction hazards.

[0020] A further object is to provide a system that can be produced in a wide range of pipe sizes so as to accommodate a wide range of sizes of swimming pools.

[0021] Another desirable object of the invention is to provide an SVRS that can operate totally on hydraulic energy, not relying upon any electrical components, and therefore, neither prone to electrical component failure nor loss of electrical power to the SVRS.

[0022] Still another object of the invention is to provide an SVRS that can be utilized to automatically clear substantially any type of pump suction fitting of debris that has blocked flow to the pump.

[0023] According to the invention, an automatic valve system functions as an SVRS. This system performs a safety vacuum release operation by reversing the direction of the flow within the main drainpipe and the return pipe of a swimming pool circulation system. As a result, the system releases a bather who has become suction-entrapped onto a suction outlet fitting and pushes the bather away under pump-forced pressure.

[0024] The invention is composed of a two-position flow-reversing means. In a first position, the flow reversing means creates a normal flow pattern by interconnecting the pump and filter influent with the pool drain line and by interconnecting the pump and filter effluent with the pool return line. In a second position, the flow reversing means interconnects the pump and filter influent with the pool return line and interconnects the pump and filter effluent with the pool drain line. Thus, in the second position the flow-reversing means creates a pressurized release flow pattern in the reverse direction.

[0025] The flow-reversing means is designed to make a smooth transition between the two flow patterns without stoppage of flow or abrupt pressure changes.

[0026] The present invention includes a vacuum sensing means for monitoring the vacuum level within the suction line of the pool circulation system. In addition, the vacuum sensing means promptly activates the flow-reversing means if the vacuum reaches a pre-selected high level.

[0027] The flow reversing means may comprise a valve powered by an automatic actuator motor that switches the valve between two positions, respectively corresponding to normal flow and reverse flow. Alternatively, this function can be achieved by use of an auxiliary pump or a hydraulic accumulator.

[0028] Preferred embodiments of the invention are hereafter described with a degree of particularity. It should be understood that this description is made by way of preferred example and is not meant to limit the scope of the present invention. The inventors claim the process of immediately reversing the direction of pump flow within a swimming pool suction pipe for the purpose of releasing and pushing away a blockage, especially an entrapped bather.

[0029] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with the description, serve to explain the principles of the invention. In the drawings:

Brief Description of Drawings

[0030]Figure 1 (Prior Art) is a schematic drawing of a representative swimming pool circulation system, showing conditions of normal flow.

[0031]Figure 2 is a schematic drawing of a representative swimming pool support system with the SVRS of the invention installed, showing conditions of normal flow.

[0032]Figure 3 is a schematic drawing of a representative swimming pool support system with the SVRS of the invention installed, showing conditions of reverse flow.

[0033]Figure 4 is a vertical cross-section of a directional control valve, showing a configuration for normal flow.

[0034]Figure 5 is a vertical cross-section of a directional control valve, showing a configuration for reverse flow.

Detailed Description

[0035] The following item numbers are used in the drawings to identify the elements of the invention and are used throughout the following description:

[0036] Swimming pool components:

[0037] 10 Pool

[0038] 12 Pool Main Drain

[0039] 14 Pool Surface Skimmer

[0040] 16 Pool Surface Return

[0041] 18 Pump

[0042] 20 Filter

[0043] 22 Heater

[0044] Circulation system components:

[0045] 24 Pool Drain Line

[0046] 26 Pool Skimmer Line

[0047] 28 Skimmer Control Valve

[0048] 30 Drain Control Valve

[0049] 32 Main Pump Suction Line

[0050] 34 Pump Discharge Line

[0051] 36 Filter Effluent Line

[0052] 38 Support System Effluent Line

[0053] 40 Pool Return Line

[0054] Propulsion-release safety vacuum release system (SVRS) components:

[0055] 42 Four-Port Multi-port Flow Reversing Valve

[0056] 44 Reversing Valve Actuator Shaft

[0057] 46 Hydraulic Valve Actuator

[0058] 48 Directional Control Valve

[0059] 50 Flow Blockage Suction Interrupter Valve (FBSI)

[0060] 52 Suction Spike Arrester

[0061] 54 Vacuum / Pressure Gauge

[0062] 56 FBSI Valve Piston

[0063] 58 Vacuum Sensor Line

[0064] 60 Actuator Control Line

[0065] Directional control valve details:

[0066] 62 Valve Body

[0067] 64 Directional Control Piston

[0068] 66 Upper Piston O-Ring

[0069] 68 Lower Piston O-Ring

[0070] 70 Separation Disc

[0071] 72 Separation Disc O-Ring

[0072] 74 Separation Disc Aperture

[0073] 76 Retainer Ring

[0074] 78 Vacuum Chamber

[0075] 80 City Water Connection

[0076] 82 Vacuum Sensor Connection

[0077] 84 Hydraulic Actuator Connection

[0078] Modern aquatic facilities such as swimming pools, hydrotherapy pools, and wading pools incorporate a water circulation system. This system maintains a safe water quality for bathers by circulating the water through sanitization, filtration, and heating processes.

[0079] A typical swimming pool circulation system is illustrated in Fig. 1, where a pump 18 creates and maintains flow within the system. The pump has an intake side that creates a low or negative pressure, which will be referred to as a degree of vacuum, within the main pump suction line 32. The pool drain line 24 feeds the suction line 32 through drain control vale 30, and pool skimmer line 26 feeds suction line 32 through skimmer control valve 28. The vacuum created by the pump 18 therefore is communicated into lines 24 and 26. This vacuum causes water within the pool 10 to enter the pool main drain 12 and the pool surface skimmer 14. An intake side of the circulation system, which may be referred to as the pool suction circulation system, includes pool main drain 12, pool surface skimmer 14, pool surface return port 16, pool drain line 24, pool skimmer line 26, skimmer control valve 28, drain control valve 30, and main pump suction line 32. Water flows into the pump 18 from these elements of the pool suction circulation system and is directed into filter 20 through the pump discharge line 34. Water then is directed through heater 22 through the filter effluent line 36. The water exits the heater 22 into the support system effluent line 38, which connects to the pool return line 40. Finally, the water returns to the pool 10 in filtered, sanitized, and heated condition through the pool surface return ports 16.

[0080] The pool main drain 12 presents the potential hazard of entrapping a bather due to suction. The pump 18 normally receives water from the pool 10 via two sources: the pool main drain 12 and the pool surface skimmer 14. Due to a variety of possible operating situations, the swimming pool circulation system can lose circulation at the pool surface skimmer 14. Then, pump 18 receives its total incoming flow of water from the pool main drain 12. In this situation, the pump 18 has become "single-sourced," and a potential hazard exists to entrap a bather due to suction at the main drain. If a bather inadvertently or intentionally blocks the flow of water into the pool main drain 12, the bather likely will become entrapped, risking injury or drowning.

[0081] In the event a bather becomes suction entrapped to a pool main drain 12 in a swimming pool 10, the present invention releases and propels the bather away from the main drain 12 by reversing the direction of flow of water within the pool drain line 24, thereby releasing the bather.

[0082]Fig. 2 shows the present invention added to the typical swimming pool circulation system of Fig. 1. In both Figs. 1&2 the direction of water flow within the drain line 24 is "normal flow,"which is from the pool 10 and towards the pump 18. Fig. 3 shows the same typical swimming pool circulation system with inclusion of the invention installed as in Fig. 2, and with the invention now actuated to provide "reverse flow." Pressurized water now flows into the swimming pool 10 at the pool main drain 12 so that any blockage at the drain inlet is propelled away from the pool main drain 12.

[0083] The present invention utilizes a four-port reversing valve 42 to reverse the direction of flow within the pool drain line 24. The preferred reversing valve is the Full Flow Multi-port Butterfly Valve described in U.S. Patent 4,774,977, which is incorporated by reference herein.

[0084] With the SVRS system installed as shown in Fig. 2, the circulation system has "normal flow," which means that water is withdrawn from the pool 10 by flowing into the pool main drain 12 and is returned to the pool 10 through the pool surface return fittings 16. The reversing valve 42 directs the water to the main pump suction line 32 from the pool drain line 24 as directed by the reversing valve 42. The reversing valve 42 also receives water from the support system effluent line 38 and directs it into the pool return line 40.

[0085] In Fig. 3, the reversing valve 42 is shown in a second configuration in which it has been moved into a position cross-connecting the port configuration of Fig. 2. Reversing valve 42 has redirected the two previously mentioned internal flow paths to create the pressurized "reverse flow" within the pool drain line 24. This second position releases an entrapped bather or obstruction from the pool main drain 12 and jettisons the obstruction or bather away from the pool main drain 12. In Fig. 3 the reversing valve 42 has redirected the water flow into the main pump suction line 32 from the pool return line 40, which, in turn, is in fluid communication with the pool surface return fittings 16. Valve 42 also has redirected the water flow from the support system effluent line 38 into the pool drain line 24, thereby temporarily creating a forceful flow of water into the swimming pool 10 at the pool main drain 12 for the purpose of clearing that fitting within the swimming pool 10 of any foreign obstruction that blocks the flow of water into the fitting.

[0086] Referring to Figs. 2 & 3, the preferred four-port reversing valve 42 is a multi-port butterfly valve with a ninety degree rotary stroke, as described in U.S. Patent No. 4,774,977. This reversing valve 42 is actuated by a standard hydraulic water-to-spring rotary valve actuator 46, which has mechanical attachment to the reversing valve 42 through the actuator shaft 44. A model 79 PS actuator produced by Asahi/America is an example of this type of actuator. Similar products are produced by other companies and are commonly used to automate a wide variety of different types of fluid control valves.

[0087] As illustrated, this hydraulic valve actuator 46 is spring-loaded and biased to position the reversing valve 42 n the "reverse flow" configuration illustrated in Fig. 3. The actuator 46 is rotated into the "normal flow" configuration by the force of water at sufficiently high water pressure ,fed into the actuator 46 and overcoming the spring loading of the hydraulic valve actuator 46. A reliable, high-pressure source of water is municipal or city water. If city water pressure is lost, the reversing valve 42 is positioned by the spring-loaded hydraulic valve actuator 46 into the biased position, which is the position which produces "reverse flow." The resulting default valve position of the reversing valve 42 is the safe valve position, which produces the reverse pressurized incoming flow at the pool main drain 12. The bias of actuator 46 eliminates any possibility of a suction entrapment hazard occurring during an outage of city water pressure.

[0088] The reversing valve 42 has first and second positions, respectively corresponding to conditions of "normal flow" and "reverse flow." The directional control valve 48 selects between these two positions. If the directional control valve 48 puts the hydraulic valve actuator 46 in fluid communication with a high reference water pressure, such as city water, the actuator 46 places the valve 42 into first or "normal flow" position. Valve 48 provides such pressure communication through the actuator control line 60. The high water pressure overpowers the springs of the hydraulic valve actuator 46, causing the actuator 46 to positions the reversing valve 42 in the "normal flow" configuration of Fig. 2. Conversely, the directional control valve 48 will puts the hydraulic valve actuator 46 in fluid communication with the inlet side of the circulation system via vacuum sensor line 58 if pressure in pool drain line 24 is sufficiently low. The low pressure is communicated to actuator 46 through the actuator control line 60. The low pressure allows the springs within the spring-loaded hydraulic valve actuator 46 to dominate, and the actuator 46 repositions the reversing valve 42 in the "reverse flow" configuration. The output water stream from pump 18 is directed into the pool through main drain 12 to provide the life-saving thrust away from the main drain 12, as illustrated in Fig. 3.

[0089] The directional control valve 48 is attached to flow blockage suction interrupter (FBSI) valve 50. The FBSI 50 is described in U.S. Patent #6,098,654 and incorporated by reference herein. Fundamentally, this valve incorporates FBSI valve piston 56, which is attached to a spring-loaded telescopic shaft. This valve is triggered by an increase in vacuum level in the intake side of the circulation system, beyond a pre-selected pressure predetermined to be dangerous. When triggered, the valve activates by extending the telescopic shaft to suddenly move the FBSI valve piston 56 outward. The position of the FBSI 50 determines whether the fluid connection between the hydraulic valve actuator 46 through the actuator control line 60 is to the city water pressure or to the intake side of the circulation system. Connection to reference or city water pressure creates the "normal flow" configuration of Fig. 2. Connection to an elevated vacuum level within the pool drain line 24 creates the "reverse flow" configuration of Fig. 3.

[0090] The operation of the directional control valve 48 is described here and illustrated in Figs. 4 & 5. Fig. 4 is a cross-sectional side view of the directional control valve 48 in the "normal flow" configuration in which it provides for fluid communication between the city water connection 80 and the hydraulic valve actuator connection 84. As illustrated in Fig. 2, this will provide city water pressure to the hydraulic valve actuator 46 through the actuator control line 60. As previously explained, in this configuration the reversing valve 42 provides for the "normal flow" configuration of the swimming pool circulation system.

[0091] In Fig. 5 the directional control valve 48 is illustrated in the "reverse flow" configuration in which it provides for fluid communication between the vacuum sensor connection 82 and the hydraulic valve actuator connection 84. As illustrated in Fig. 3, this will provide elevated vacuum level to the hydraulic valve actuator 46 through the actuator control line 60. As previously explained, in this configuration the reversing valve 42 provides for the "reverse flow" configuration of the swimming pool circulation system.

[0092] With further reference to Fig. 4, the directional control valve 48 is in the "normal flow" position. The separation disc 70 separates the vacuum chamber 78 from the rest of the interior of the valve body 62. The separation disc 70 seals to the interior of the valve body 62 with the separation disc o-ring 72 and is retained by the retainer ring 76. The directional control piston 64 is in an upper position, thereby sealing the separation disc aperture 74 closed with the upper piston o-ring 66. The lower piston o-ring 68 is not engaged into the city water connection 80, thereby allowing fluid communication into the valve body interior 62 from the city water connection 80 and then into the hydraulic actuator connection 84. The directional control piston 64 is lifted into this configuration by the force of the city water pressure exerted on the bottom of the directional control piston 64.

[0093] Referring now to FIG. 5, the directional control valve 48 is in "reverse flow" position. The directional control piston 64 is in the lower position, sealing the city water connection 80 closed with the lower piston o-ring 68, and the upper piston o-ring 66 is now not engaged into the separation disc aperture 74, thereby allowing fluid communication within the valve body 62 between the vacuum chamber 78 and the hydraulic actuator connection 84. The directional control piston 64 has now been forced into this secondary lower configuration by the downward force created by the flow blockage suction interrupter valve 50, which has extended its piston 56 down against the top of the directional control piston 64. Now, as shown in Fig. 3, the hydraulic valve actuator 46 has been placed in fluid communication with the elevated vacuum of the pool drain line 24, allowing the springs within the hydraulic valve actuator 46 to reposition the reversing valve 42 into the secondary "reverse flow" configuration.

[0094] Once again, referring to Fig. 2, the protective cycle of this invention provides begins when an elevated vacuum level is created within the drain line 84 by a suction entrapment incident, which creates a blockage of water flow at the pool main drain 12. This elevated vacuum level is transmitted to the directional control valve 48 by the vacuum sensor line 58. Now, referring to Fig. 4, the elevated vacuum level is communicated to the vacuum chamber 78 inside of the directional control valve 48 through the vacuum sensor connection 82. The FBSI valve 50, which is attached to the directional control valve 48, is triggered by the increase in vacuum level and extends its FBSI piston 56, which, as illustrated in Fig. 5, in turn pushes the directional control piston 64 down into the secondary configuration to initiate the transfer of the system flow pattern from the "normal flow" configuration to the secondary, life-saving configuration of "reverse flow".

[0095] As further shown in Fig. 2, the vacuum sensor line 58 includes a suction spike arrester 52. When the swimming pool pump 18 initially starts, a momentary spike in negative pressure (vacuum) occurs within the vacuum sensor line 58. The suction spike arrester 52 is simply a captive air reservoir that provides a shock absorbing function to quell this spike in vacuum so that the spike which occurs during pump startup does not trigger the FBSI valve 50 and cause an unnecessary cycle of the invention.

[0096] Additionally, a vacuum/pressure compound gauge 54 is installed at the same location as the suction spike arrester 52. The purpose of this gauge 54 is to provide the swimming pool operator with a real time reading of the vacuum level or pressure within the pool drain line 24 .

[0097] Referring once more to Fig. 3, with the system in the secondary life-saving configuration of "reverse flow," the drain line 24 has been converted from vacuum to positive pressure. Looking again at Fig. 5 one can see that this positive pressure is transmitted into the vacuum chamber 78, which in turn forces the FBSI piston 56 back up into the FBSI valve 50. This automatically resets the system for "normal flow" by allowing the water pressure within the city water connection 80 to once again force the directional control valve piston 64 into the upper position of Fig. 4. This returns the direction of flow within the swimming pool circulation system to the "normal flow" configuration and completes the cycle of the system.

[0098] The cycle of events for this invention begins with the swimming pool circulation system running in "normal flow", as shown in Fig. 2. A bather becomes entrapped at the pool main drain 12 on the floor of the swimming pool 10. The FBSI valve 50 is triggered by the increase in vacuum within the pool drain line 24, and the circulation system is immediately shifted to "reverse flow" by the reversing valve 42, shown in Fig. 3. The bather is rescued by being propelled away from the pool main drain 12. The resulting positive pressure within the drain line 24 resets the FBSI valve 50. Finally, the circulation system is returned to the "normal flow" configuration illustrated in Fig. 2 by the reversing valve 42, rearmed to rescue any subsequent bathers who may become entrapped.

[0099] The forgoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be regarded as falling within the scope of the invention. 

Claims
 1. In a water circulation system of an aquatic facility, having a water intake side including at least one underwater intake port and having a water output side including at least one output port, and having a pressurized water output source directing a water stream into the aquatic facility through the output port and withdrawing a water stream from the aquatic facility through the water intake port, an improved safety vacuum release system for propelling a blockage away from a blocked underwater intake port of the circulation system, comprising: a flow valve moveable between a first position withdrawing a water stream from the aquatic facility through said underwater intake port and a second position feeding a water stream into the aquatic facility through the intake port; and an actuator responsive to the level of water pressure on the water intake side of the circulation system, operatively connected to the flow valve, selectively actuating the flow valve to move from first position to second position in response to a pre-selected low level of water pressure on the water intake side of the circulation system, thereby reversing the direction of water flow in the intake side to direct water out the intake port for propelling blockage away from the intake port.
 2. The safety vacuum release system of Claim 1, further comprising: a pump that provides an intake side and an output side; wherein, in said first position the flow valve interconnects said underwater intake port with said intake side of said pump, and in said second position the flow valve interconnects the underwater intake port with said output side of the pump.
 3. The safety vacuum release system of Claim 2, wherein: said flow valve comprises a four-port reversing valve; the flow valve is positionable in said first position, simultaneously interconnecting first and second pairs of the valve ports, wherein the first pair of interconnected valve ports connects said underwater intake port with said intake side of the pump for withdrawing a water stream from the aquatic facility, and the second pair of interconnected valve ports connects said output side of the pump with an output port for discharging a water stream to the aquatic facility; and the flow valve is positionable in said second position, cross-connecting the valve ports from the first position, such that the intake port is connected to the output side of the pump for discharging a water stream through the intake port into the aquatic facility, and the intake side of the pump is connected to an output port of the aquatic facility.
 4. The safety vacuum release system of Claim 1, wherein said actuator is spring-biased to move said flow valve to second position.
 5. The safety vacuum release system of Claim 4, wherein said actuator is operatively connected to a source of pressurized water external of the aquatic facility, overcoming the bias toward second position of the flow valve when external water pressure is sufficiently high.
 6. The safety vacuum release system of Claim 5, wherein said source of water pressure external of the aquatic facility is a municipal water system.
 7. The safety vacuum release system of Claim 1, further comprising: a directional control valve in communication with said actuator, inducing the actuator to selectively move said flow valve between first and second positions, wherein the directional control valve is in operative communication with a reference source of water pressure and the water pressure on the water intake side of the circulation system; and a means for selectively switching the directional control valve between a normal flow position inducing the actuator to position the flow valve in first position and a reverse flow position inducing the actuator to position the flow valve in second position, wherein normal flow position of the directional control valve communicates reference water pressure to the actuator and reverse flow position of the directional control valve communicates the water pressure on the water intake side of the circulation system to the actuator.
 8. The safety vacuum release system of Claim 7, wherein said means for selectively switching the directional control valve between normal and reverse positions comprises: a pressure detecting device having a sliding piston moveable at a pre-selected water pressure level, in pressure communication with said water intake side of the circulation system, wherein said sliding piston is operatively connected to said directional control valve for switching it from normal to reverse position in response to detecting a water pressure lower than said pre-selected level and switching it from reverse to normal position in response to detecting a water pressure higher than the pre-selected level.
 9. A method of operating a safety vacuum release system in a water circulation system of an aquatic facility, having a water intake side including at least one underwater intake port and having a water output side including at least one output port, and having a water pressure source directing a water stream into the aquatic facility through the water output side and withdrawing a water stream from the aquatic facility on the water intake side, comprising: first, pre-selecting a water pressure level for actuating a safety vacuum release system; second, monitoring water pressure level on the intake side of the circulation system; third, detecting a drop in water pressure level below said pre-selected pressure on the intake side of the circulation system; and fourth, reversing direction of flow between the intake and output sides of the circulation system, directing the water stream into the aquatic facility through the intake port to propel blockage away from a the intake port and restore a pressure level greater than the pre-selected level on the intake side of the circulation system.
 10. The method of Claim 9, further comprising: fifth, after said fourth step, further monitoring water pressure level on the water intake side of the circulation system; sixth, detecting a water pressure level above said pre-selected pressure on the intake side of the circulation system; and seventh, again reversing the direction of flow between the water output side and water intake side of the circulation system, directing a water stream into the aquatic facility through the water output side of the circulation system.
 11. 11. A method of operating a safety vacuum release system in an aquatic facility having a water intake system including at least one underwater intake port, having a water pressure source withdrawing a water stream from the aquatic facility into the water intake system, comprising: first, pre-selecting a water pressure level for actuating a safety vacuum release system; second, monitoring water pressure level in the intake system; third, detecting a drop in water pressure level below said pre-selected pressure in the intake system; and fourth, in response to said third step, reversing direction of flow in the intake system, directing a water stream into the aquatic facility through the intake port to propel blockage away from a the intake port and restore a pressure level greater than the pre-selected level in the intake system. 